


Let's Talk About Sex: Vampire/Slayer Biology in the Barbverse

by Barb Cummings (Rahirah)



Series: The Barbverse [128]
Category: Angel: the Series, Buffy the Vampire Slayer
Genre: Meta, Vampire Sex, Vampire Slayer(s), barbverse, vampire biology
Language: English
Status: Completed
Published: 2014-07-28
Updated: 2014-07-28
Packaged: 2018-02-10 20:18:58
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,886
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/2038734
Author URL: https://archiveofourown.org/users/Rahirah/pseuds/Barb%20Cummings
Summary: <blockquote class="userstuff">
      <p>This essay contains spoilers for the entire Barbverse series.  Those who remember  earlier versions of this essay may note that I've made a few minor changes and elaborations in the way things work. This version supercedes all previous versions, at least until I get a better idea.  This is only intended to apply to my own 'verse; I'm not making ANY claims that this has any relation at all to the way the inheritance of Slayerness works in canon. I've tried not to do anything that outright contradicts canon, but I'm making quite a lot of this up from the whole cloth.</p>
    </blockquote>





	Let's Talk About Sex: Vampire/Slayer Biology in the Barbverse

**Author's Note:**

> This essay contains spoilers for the entire Barbverse series. Those who remember earlier versions of this essay may note that I've made a few minor changes and elaborations in the way things work. This version supercedes all previous versions, at least until I get a better idea. This is only intended to apply to my own 'verse; I'm not making ANY claims that this has any relation at all to the way the inheritance of Slayerness works in canon. I've tried not to do anything that outright contradicts canon, but I'm making quite a lot of this up from the whole cloth.

Slayers

The following is a HUGE over-simplification. The traits in question are almost certainly not determined by a single gene, but by a complex of many, many interrelated genes, with added mystical components. (IOW, if it doesn't make sense, a wizard did it.) But for simplicity's sake, let's pretend that Potentialness is determined by a single gene with two possible alleles, d and _d_. _d_ is dominant to d. Thus there were originally three possible combinations of alleles: 

_dd_ = Potential  
 _d_ d = Potential  
dd = normal human 

Female carriers of _d_ are less likely to survive to childbearing age than their dd counterparts (due to getting called and subsequently killed by vampires), so it's remained comparatively rare in the population at large. This is, by the way, one reason I decided not to make the gene for Potentialness sex-linked; having an unexpressed reservoir of the gene in the male population was a good way to keep the Slayer line from dying out in times when the number of female carriers dipped dangerously low due to running through Slayers like potato chips. Kill off all the females, and in a generation or so there will still be more Potentials born to _d_ -carrying fathers. Due to the nature of Slayer magic, the power never becomes active in the male carriers of _d._

There is some evidence that having a _dd_ genotype increases the likelihood of a Potential being called, and somewhat shakier evidence that it may affect the degree of power a Slayer has once called, but no studies have been undertaken which prove this. 

In the Barbverse, Buffy Summers made her own deal with the demon essence that created the Slayer line: In return for her liberating it from the Shadow Men and bringing it back with her into the world, it would 'live and grow' not just within her, but within the several dozen under-powered Slayers whom the Watcher's Council had created in a bungled attempt to recruit a Slayer army. When this demon essence merges with a Slayer or a Potential, it transforms _d_ into a third variant, _**d**_. 

There are two major differences between _**d**_ and _d_. One, _**d**_ does not require any sort of calling for the mystic components to activate. It simply activates at puberty, gradually gaining strength over the next few years. Two, it will activate for both male and female carriers. Just as with _d_ , _**d**_ is expressed differently in males than it is in females. A female carrier has the standard Slayer powers. A male carrier, however, will have a slightly different suite of powers: They will not be as strong as a female Slayer, and they do not have prophetic dreams. They do, however, possess enhanced senses of smell, hearing, and night vision. Angel's son Connor and Buffy and Spike's son Alex are examples of male carriers of _**d**_ in the Barbverse. (Connor is, technically, a miracle baby whipped up by the Powers That Be, but you get the idea.)

Carrying the _d_ allele doesn't have any effect on whether or not a person can be vamped. Active old-style Slayers who are vamped get a double dose of magical powers; their original Slayer powers plus the vampire demon. (Note that because Barbverse Kennedy did not have her full Slayer powers when Angelus turned her, she is only a normal-powered vampire, not supervamp.) _**d**_ -carrying Slayers of either sex, however, cannot be vamped. It is speculated that this is because the Slayer-demon essence lingers long enough to prevent the new vampire demon from possessing the corpse. Living vampires can't be re-vamped either. In both cases, if they are drained by a regular vampire, they will just die even if they ingest the vampire's blood. 

Note that once Buffy brought the demon essence out of the Shadow Men's pocket dimension and into herself and the several dozen other Slayers who needed its power, old-style Slayers are no longer called by the death of an existing Slayer. The only source of new Slayers in the Barbverse is the children of existing Slayers and/or living vampires. Because of this, it is likely that the presence of _d_ may gradually increase in the human population, as more female carriers survive to pass it on. In theory, it might be possible to re-create the initial ritual done by the Shadow Men, and create a new line of old-style Slayers. So far, no one has been stupid enough to attempt this. 

Vampires

In the Barbverse, when a vampire is given an infusion of Mohra blood, the human host body is returned to biological life. When this occurs, one of three things can happen. 

1\. If the vampire has a soul, they will become an ordinary human again, retaining their original genotype. 

2\. If there is not sufficient integration between the demonic animus and the host body, the host body will return to fully human, albeit soulless, life. The demonic animus, unable to maintain its foothold within a living host body, will dissipate, just as when a vampire is staked. The revivified host body is invariably severely impaired, and will generally die within a week unless maintained by artificial means. Attempts have been made to restore the missing soul of such a revivified body, but so far with little success. Obviously it is preferable to re-soul the vampire before attempting to revivify them, but this, alas, has its own risks and difficulties. 

3\. If there is sufficient integration between the demonic animus and the host body, the regenerative powers of the Mohra blood meld the traits of the demonic _animus_ with the traits of the human host body, creating a new type of living demon which has most of the powers and limitations associated with undead vampires. Living vampires are mortal, reproducing, aging and dying in the same manner as humans, but they are exceptionally strong, have enhanced senses, need blood to survive, burn in sunlight, etc. The important point for the purposes of this essay is that the Mohra blood creates a new variant of the allele, D. Mohra blood will preferentially transform d into D; _d_ will only transform into D if the host body is a _dd_.) 

Precisely what it takes for a vampire to be 'sufficiently integrated' is debatable. There has been little experimentation, as Mohra blood is extremely difficult to come by, as Mohra demons are loath to part with any and generally object strenuously to attempts to remove it by force. As of this writing, only three unsouled vampires are known to have survived the Mohra blood transformation. All of them were individuals who had, prior to their transformation, maintained non-adversarial relationships with humans for several years, either by preference or by necessity, and who willingly retained many habits and preferences from their human days. It may also be relevant that all of them chose to undergo the Mohra blood treatment, rather than having it forced upon them. The vast majority of unsouled vampires upon which this process has been tested by the ever-inquisitive research department at Wolfram & Hart are no longer available for comment. 

Vampire/Slayer Reproductive Biology

Sperm capacitation in male live vampires, and the development of sperm-receptive carbohydrate groups in zona pellucida glycoproteins in female live vampires, is greatly accelerated and enhanced by the ingestion of small amounts of their partner's blood. It is also thought that the physical act of biting is a spur to ovulation in the female and increased sperm production in the male. This is most notably the case when the vampire has a human or Slayer partner. The chances of one live vampire impregnating another without biting are about the same as those of one human impregnating another; biting raises the chances of conception by approximately fifteen to twenty percent. The chances of a live vampire impregnating, or becoming pregnant by, a human are virtually zero unless there is biting involved. With the ingestion of blood, the chances of conception skyrocket. (Therefore, a very simple method of birth control for a live vampire/human couple would be to refrain from biting while engaged in vaginal sex. This is perhaps easier advice to give than to put into practice.) 

Live vampires can successfully reproduce with one another, with post-demon dust active Slayers, or with unactivated Potentials. However, vampire/Potential and vampire/human crossings are risky, as Dd embryos are not viable, invariably developing various severe birth defects and spontaneously aborting in the first trimester. In addition, humans with a dd genotype or even an unactivated _d_ d or _dd_ genotypes are less well equipped to handle the process of fertilization without taking injury. There is considerable evidence that live vampires are able to detect the differences in body chemistry in humans who carry the _d_ or _**d**_ allele by scent, and find these humans particularly sexually attractive, but this is no guarantee that no vampire will ever fall for a dd human. 

Examples

D is dominant to _**d**_ , _d_ and d. _**d**_ is dominant to _d_ and d. _d_ is dominant to d. So: 

_dd_ = Potential  
 _d_ d = Potential  
 _ **dd**_ = Post-demon dust Slayer  
 _ **d**_ d = Post-demon dust Slayer  
 _ **d** d_ = Post-demon dust Slayer  
dd = normal human  
DD = living vampire  
D _d_ = living vampire  
D _ **d**_ = living vampire  
Dd = not viable 

Buffy Summers, in the Barbverse, was born a _dd_. Post-demon dust, she is a _**dd**_. Dawn Summers is a normal dd human, so both Joyce and Hank Summers must have been _d_ d. William Pratt was also born d _d_. Spike, post-Mohra-blood, is D _d_. Sam Lawson and Evie Maldonado were both born dd; post-Mohra blood, both are DD. 

Here are the ways that some of these pairings work out. Note that these are only statistical averages - just because Bill and Toni have, say, two Slayer children, that doesn't mean the third child will be a vampire - each conception has exactly the same odds of being one thing or another as the next.

  
| Spike (D _d_ )  
---|---  
D | _d_  
Buffy **(dd)** | **d** |  **d** D |  **d** _d_  
**d** |  **d** D |  **d** _d_  
  
IOW, odds are that about half of Spike and Buffy's children will be vampires, and half Slayers.

  
| Bill (D ** _d_** )  
---|---  
D | **_d_**  
Toni (d _d_ )  | d | dD | d ** _d_**  
_d_ |  _d_ D |  _d_ ** _d_**  
  
Odds are about half of Bill and Toni's children will be Slayers, one-quarter will be vampires, and one-quarter will miscarry due to the non-viable Dd genotype. (Their first child, in fact, was miscarried; Nita is their second, and they resorted to in vitro fertilization to make certain that any future children would be viable.) Bill and Toni might possibly have some fully human grandchildren, if one of their children ends up _d_ d and has children with another human.

  
| Connie ( ** _d_** _d_ )  
---|---  
**_d_** | _d_  
Lawson (DD) | D | D ** _d_** |  D _d_  
D | D ** _d_** |  D _d_  
  
All Connie and Lawson's children will be vampires, but they might, depending upon whom their children end up with, have Slayer or Potential grandchildren. I had originally included a chart for Alex in here, but as it turns out, he ends up with Evie and his chart looks exactly the same as Connie's does. I've also taken out the speculative charts I did for Vicki and Jessica because I have no idea who, if anyone, they'd end up with at this point.


End file.
